Subject: Re: [bug#51655] [PATCH] build-system: haskell: Add‘package-with-explicit-haskell’ procedure.

From: zimoun <[email-masked]>
Date: Sun, 19 Dec 2021 10:23:05 +0100

Hi,

On Sun, 19 Dec 2021 at 09:47, Xinglu Chen <[email-masked]> wrote:

>>> +@lisp
>>> +(use-modules (guix build-system haskell))
>>> +
>>> +(define (default-haskell-8.8)
>>> +  ;; Lazily resolve the binding to avoid a circular dependency.
>>> +  (let ((haskell (resolve-interface '(gnu packages haskell))))
>>> +    (module-ref haskell 'ghc-8.8)))
>>> +
>>> +(define package-with-haskell-8.8
>>> +  (package-with-explicit-haskell (delay (default-haskell-8.8))
>>> +                                 "ghc-" "ghc-8.8-"
>>> +                                 #:variant-property 'ghc-8.8-variant))
>>> +@end lisp
>>
>> As Lars said, an instance is missing, IMHO.
>
> Not sure what you are referring to here, what exactly do you mean with
> “instance”?

For example, something as:

    (package-with-haskell-8.8 hledger)

Cheers,
simon